[Selective suppression of the direct and feedback "fast" inhibition during local administration of picrotoxin in the CA1 region of rat hippocampal slices].

Application of picrotoxin to apical dendrites in the CA1 area of the rat hippocampal slices increased the duration of focal potentials (FP) in the stratum radiatum but did not affect the unit activity spikes' amplitude in the stratum pyramidalis, the finding suggesting a suppression of the feed-forward inhibition with no effect upon the recurrent one. The data obtained shows that, under conditions normally used for studying the NMDA-EPSP feed-forward, the inhibition is not invariably suppressed and may affect the results of the studies.